The technique to extract information such as an attribute of a word (for example, product name and price of the product) from a web page or a document has been known. With such a technique, particular information within a document can be easily organized (for example, extracting the list of specifications of products from a document and making a table).
However, if information to be extracted varies for each document, it is troublesome to select an attribute. The conventional technique to classify plural documents into designated categories and to determine what kind of information is to be extracted in accordance with the classification may be used.